1. Field of the Invention
This invention relates to an inclination sensor
2. Description of Related Art
There are various designs of inclination sensors.
Previously, mercury was very often used in order to detect the shifting position of the mercury in the inclination sensor. For reasons of environmental concerns, the application of such mercury sensors is no longer legal in most cases.
Thereafter, pendulum sensors are commonly used. In this context, a pendulum always assumes an exactly vertical position corresponding to the current gravitational force and possibly attenuated with the pendulum disposed in an attenuation chamber filled with attenuation fluid.
On a support axis of the pendulum, which permeates the pendulum chamber towards the sensor chamber, an angle sensitive element whose rotational position was detected is disposed in the sensor chamber, e.g. an incremental rotating disk which is scanned by a reading head.
Disadvantages in this context were the long-term tight-pass-through of the pendulum shaft through a divider wall and the long-term smooth operation of the bearing of the pendulum axis which allow a fast adaptation of the pendulum position to gravity, also when angular changes are minor.
Besides that, it is known from German Patent No. DE 203 14 275 to no longer run the pendulum axle through the divider wall into the sensor chamber but to dispose an indicator magnet on the pendulum axle within the pendulum chamber and to sense the rotational position of this magnet contact-less through the non-magnetizable divider wall, through a magnetosensitive sensor, which is disposed on an opposite side in the sensor chamber.
Also, there still exists the persistent problem that relatively high support forces are to be received in a small central bearing axle reliably and with extremely low static friction in order to make the pendulum deflect even upon the smallest angular changes.
It is, furthermore, known to use singular Hall elements as magnetosensitive elements, thus Hall effect sensors, as described in U.S. Pat. No. 5,365,671.
A single Hall Effect sensor, however, can only measure the intensity of the magnetic field, in which it is disposed, and thus the measuring result is strongly dependent on the distance of the Hall sensor from the activating indicator magnet.
Therefore, the moving body which aligns itself with gravity and which is mounted to the indicator magnetic is received in a very tight surrounding support housing. Thus, in order to avoid the friction at the surrounding support surfaces, the cavity in which the moving body is located is completely filled with a fluid whose specific weight corresponds to the one of the pivoting body, so that the body floats in the fluid quasi weightlessly (column 2, line 45 of U.S. Pat. No. 5,365,671). Thus, this is a pendulum with a center of gravity outside of the point of rotation of the pivoting body, whose support is formed through the outer surrounding guide surfaces.